Electric meter



W. C. FISH.

, ELECTRIC METER. N0. 575,777. 7 Patented Jan. 26, 1897.

3 W X J S s w :3

VS/ITNEESES- UNlTED STATES PATENT Urrrcn.

\VALTER C. FISH, F LYNN, MASSACHUSETTS, ASSIGNOR TO THE GENERAL ELECTRICCOMPANY, OF NEW YORK.

ELECTRIC METER.

SPECIFICATION forming part of Letters Patent No. 575,777, dated January26, 1897.

Application filed October 16, 1896. Serial No. 609,115. (No model.)

To all whom it may concern: nected. The circuit ad is a shunt-circuitbe- Be it known that I, WALTER O. FISH, a cititween the brush B and themain m; that is, zen of the United States, residing at Lynn, in ashunt-circuit around the fine-wire shuntthe county of Essex, State ofMassachusetts, field coils S S. 55 have invented certain new and usefulIm- Included in the circuit a d are brushesbb',

provements in Electric Meters, (Case No. 465,) bearing upon contacts fof a commutator C,

of which the following is a specification. mounted on a worm-wheel W,forming one of This invention relates to electric meters of a train ofgear-wheels O of the meter-regthe Thomson type, and has for its objectto istry mechanism and shown in dotted lines. 60 IO prevent the creepingof electric meters of The worm-wheel W meshes with a worm in this type,in which an initial starting-torque, on the shaft X of the meter A.During the intended to compensate for the friction of the revolution ofthe wheel W the contacts altermoving parts, is produced by continuingthe nately close and open a circuit between the fine-wire shunt-circuitthrough-a field-coil cobrushes b b, which shunts at intervals the 65 I 5incident in position with the main field-coil fine-wire field-coils S S,and thereby periodafter leaving the armature of the meter, the icallyduring the movement of the meter refine-wire circuit comprising also andin larger moves the in fiuence of the initial-energy coils,partanon-inductive resistance, the inductive or at least weakens them sothat the meter resistance and armature being located in the will bestopped, except when current flows 7o shunt-circuit and the field-coilbeing conthrough the coarse-wire coils of the meter, as nected in serieswith the mains of the circuit when lights are turned on. With thisarrangein which the meter is connected. ment the meter will creep, asusual, until The invention consists in an apparatus for the circuit iscompleted between the brushes periodically, during the movement of theme- I) b, and it then stops. The time during which 7 5 ter, removing theinfluence of the init-ial-encircuit is established in this manner may ofergy coil, or at least in weakening it, to the course be anythingdesired by selecting the end that the meter shall be stopped exceptinnumber or breadth of the segments of the case current flows through thecoarse-wire commutator borne upon the wheel W. If the coils of themeter, as when lights are turned ratio of gearing between the shaft Xand the 80 on. This effect is accomplished by shunting wheel W be as oneto one hundred, then cona fine-wire field-coil at intervals by means ofnection between the brushes b b will be estabcontacts closed and openedduring the revolished once in every twenty-five revolutions lution ofthe meter mechanism. of the meter, or rather more than this, allow- Inthe accompanying drawings, Figure 1 is ing for the breadth of thesegments, as indi- 85 a diagrammatic illustration of the manner of catedin the drawings.

carrying out the invention. Fig. 2 is a modi- It might be supposed thatwithdrawing the fication thereof. effect of the fine wire field-coilswould impair A is the armature of the meter; 13 B, its the accuracy ofthe registry of the meter, and brushes; m n, the mains of the circuitinwhich such would be the case were it not for the fact 0 the meter isconnected, and L L lamps or other that a ready means of compensation isfound translating devices in said circuit, the current by adjusting thenumber of turns of the fineof which is to be measured by the meter. wirefield-coil. Thus assuming that these M M are the main field-coils, and SS finefine-wire field-coils are shunted one-third of wire shunt-fieldcoils coincident in position the time and in circuit two-thirds of thetime 95 with the main field-coils M M, and forming a and that themeter-readings are five per cent. continuation of the fine-wireshunt-circuit ce, too low it is simply necessary to increase the saidcircuit 0 e comprising in larger part a number of turns of the fine-wirecoil to comnon-inductive resistance R, and said non-inpensate for thisloss by an equal accelerating ductive resistance, armature A, and thefieldaction during the time that the fine-wire field- 100 coils beingconnected in shunt between the coil is energized, and evidently thisadjustmains of the circuit in which the meter is conment for accuracy ofregistration may be used with any number of closures between Z) and b orfor various durations of closure. The closure of said circuitone-third'of the time has given accurate results. It is of courseevident that the circuit through S S need not be entirelyshort-circuited, but may be so weakened as to produce the same resultsas, for instance, are produced by a resistance in the branch (L d.

W'hile this invention has been shown as employed in an apparatus tomeasure a direct current, it may be adapted to one for measuring analternating current, as illustrated in Fig. 2, where the inductiveresistance is omitted, and instead a transformer T is located in themains and a step-down transformer T is in circuit with the mains and thearmature A of the meter, with the same effect of weakening the field asin the case set forth in connection with Fig. 1. In Fig. 2 the brushes(2 I) are shown in position between the contacts f of the commutator Oof worm-wheel \V, in which position the shunt-field is in circuit, whilein the position of the brushes 1) 1) shown in Fig. l the shunt-field iscut out.

The commercial use of electric meters of certain types has developed thefact that when the meter is installed in a position where it is subjectto vibration, and also when the potential between the mains rises to avalue higher than the normal potential, the meter is apt to creep, as itis termed; that is, under such conditions it slowly moves and registersa consumption of energy when none should have been recorded. The objectof the present improvement is to prevent this effect.

Vhat I claim is 1. In an electric meter, the combination of 1 anarmature, a field-coil therefor, recording mechanism actuated by thearmature, and means for weakening the field periodically, or atintervals, as set forth.

2. In an electric meter, an armature in shunt to the mains, aninitial-energy coil, and means for periodically or intermittentlyweakening the initial-energy coil during the movement of the meter, asset forth.

3. In an electric meter, an armature in shunt to the mains, anon-inductive resistance in the shunt-circuit, an initial-energy coil,and means for periodically or intermittently weakening theinitial-energy coil, as set forth.

et. In an electric meter, an armature in shunt to the mains, anon-inductive resistance in the armature-circuit, a field-coil, andmeans for periodically or intermittently weakening the field, as setforth.

5. In an electric meter, an armature in shunt to the mains, afield-coil, and means for periodically or intermittently weakening thefield during the movement of the meter, as set forth.

6. In an electric meter, an armature arranged in shunt to the mains,field-coils in the main circuit, supplemental field-coils in shunt tothe mains, a non-inductive resistance in the armature-circuit, and meansfor periodically or intermittently weakening the field, as set forth.

In witness whereof I have hereunto set my hand this 14th day of October,1896.

WALTER C. FISII. \Vitnesscs:

\V. LEMP, ALFRED PAUL.

